This talk will cover several topics of current interest in understanding the QCD partonic picture.
We discuss some aspects of the recent LSS combined analysis of polarized DIS and SIDIS reactions; in particular the questions of the strange quark polarization and higher twist terms. We examine the derivation of the longitudinal and transverse angular momentum sum rules and discuss their present status. Finally, we comment on the controversy concerning the definition of quark and gluon angular momentum and suggest that Ji’s definitions are untenable.
Imperial College, London (UK)